Question

consider the following code

addHash("hash");

bool addHash(char* hash) {
    HKEY hKey = 0;
    int code = RegOpenKey(HKEY_CURRENT_USER, subkey, &hKey);

    const int length = strlen(hash)+1;
    WCHAR whash[100];
    MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, hash, strlen(hash), whash, 100);
    LONG setRes = RegSetValueEx(hKey, L"hash", 0, REG_SZ, (LPBYTE)whash, strlen(hash)+1);

    return true;
}

After code is compiled and executed “ha” is puted into registry. Can somebody tell me where the problem is?

Thank you in advance!

Answer 1

The last argument is the number of bytes, not the number of characters, that the second last argument points to.

So the first five bytes (strlen(hash) + 1) of whash will be stored in the registry. Change to:

LONG setRes = RegSetValueEx(hKey,
                            L"hash",
                            0,
                            REG_SZ,
                            (LPBYTE)whash,
                            (wcslen(whash) + 1) * sizeof(WCHAR));

You may also need to initialise whash (I don’t think MultiByteToWideChar() adds a null terminator for you):

WCHAR whash[100] = { 0 };